Apparatus and method for obtaining core samples from soil and rock masses

ABSTRACT

A core sample is removed from a soil or rock mass by boring a hole in the mass to a depth at which sampling is to begin and thereafter cutting a second hole in extension of the first hole and of a smaller diameter. The second hole is of a length equal to the desired sample and the second hole is filled with a hardenable binder such as cement whereupon a rigid reinforcing member is introduced into the still fluid binder for the depth of the second hole. After the binder has hardened a core of a diameter equal to the first hole is cut from the mass, the core being inclusive of the binder and reinforcing member with an intact surrounding sample of the mass.

Elite States atent [72] Inventor Manuel Coelho Mendes da Rocha Lisbon, Portugal [21] Appl' No. 33,559 [22] Filed May 1,1970 [45] Patented Jan. 4, 1972 [73] Assignee Laboratorio Nacional de Engenharia Civil Lisbon, Portugal [32] Priority July 24, 1969 [33] Portugal [31] 52 164 [54] APPARATUS AND METHOD FOR OBTAINING CORE SAMPLES FROM SOIL AND ROCK MASSES Primary ExaminerStephen J. Novosad Attorney-Waters, Roditi, Schwartz & Nissen ABSTRACT: A core sample is removed from a soil or rock mass by boring a hole in the mass to a depth at which sampling is to begin and thereafter cutting a second hole in extension of the first hole and of a smaller diameter. The second hole is of a length equal to the desired sample and the second hole is filled with a hardenable binder such as cement whereupon a rigid reinforcing member is introduced into the still fluid binder for the depth of the second hole, After the binder has hardened a core of a diameter equal to the first hole is cut from the mass, the core being inclusive of the binder and reinforcing member with an intact surrounding sample of the mass.

mammal 41972 31531334 SHEET 1 OF 2 APPARATUS AND METHOD FOR OBTAINING CORE SAMPLES FROM SOIL AND ROCK MASSES BRIEF SUMMARY OF THE INVENTION The invention relates to the sampling of soil and rock masses and particularly the obtaining of intact samples representative of the formations under study.

An object of the invention is to provide a method and means for removing such intact samples from the fan-nations under study.

A further object of the invention is to remove samples in the form of stable cores without disturbance of the different layers of soil or rock mass or any joints or faults therein.

Yet another object of the invention is to provide a method and means for the above purpose which is simple in use and avoids the need for the common boring techniques currently employed.

According to the invention a core sample is obtained from a soil or rock mass reinforced with a member bonded to the soil or rock mass by means of a binder so as to obtain a nondisturbed and intact core sample. The method of the invention can be applied all along the hole or solely at the locations where the conditions of the soil or rock mass render it advisable.

In accordance with the invention, there is provided a method of obtaining samples from soil and rock masses, said method comprising boring a hole into a mass to a depth, beyond which, a sample is to be removed, cutting a second hole in extension of the first hole and to a depth equal to the depth of the desired sample, the second hole being of smaller diameter than the first hole, filling the second hole with a binder and a reinforcing member, allowing the binder to harden and cutting a core from the mass inclusive of the binder and reinforcing member with an intact sample surrounding the same.

In further accordance with the invention, there is provided apparatus for obtaining a sample from soil and rock masses in which a hole is bored to a depth, beyond which, a sample is to be removed, said apparatus comprising means for cutting a second hole in extension of the first hole and to a depth equal to the depth of the desired samples, means for introducing a binder into the second hole to fill the same, means for introducing a reinforcing member into the binder, and means for cutting a core from the mass, said core being inclusive of the binder and reinforcing member with an intact sample surrounding the same.

Said means for cutting the second hole comprises rotatable bore rods, a core barrel driven by said bore rods, a drill bit on said core barrel, and guide means for guiding the travel of said core barrel, and guide means for guiding the travel of said core barrel. The guide means comprises a sleeve member engaged in said first hole and including means guidably engaging said core barrel.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevation view showing a hole bored in a soil or rock mass;

FIGS. 2-6 are elevation views showing various stages of operation for removing a core sample from the mass;

FIG. 7 is an elevation view partly in section of apparatus for drilling a second hole in extension of a first bore hole; and

FIG. 8 is an elevation view partly in section of apparatus for carrying out an intermediate stage of operation.

DETAILED DESCRIPTION The invention contemplates the integral sampling of soil and rock masses M, that is, to obtain samples that are perfectly representative of the formations to be studied, by means of devices that cut and'remove cores without disturbing the different layers of the soil or rock mass, or the joints, faults, fractures, etc. and their infillings.

As seen in FIG. 1, a hole H is bored in the soil or rock mass M to a depth, beyond which, core samples are sought. The

hole may be vertical or not. The diameter of the hole is selected on the basis of the desired diameter of the core as will become apparent hereafter.

A second hole h is then cut extending from the bottom of hole H as shown in FIG. 2. The hole h is coaxial with hole H and is cut to a depth equal to the length of the desired core sample.

The hole h is then filled with a settable or hardenable binder such as cement grout, concrete, plastic material or the like. The binder completely fills hole h and substantially expels all water and air which might otherwise be contained therein. The binder may be dyed with suitable color for identification purposes or the like. The binder is selected to have good adhesion with the soil or rock and to a reinforcing member 2 to be subsequently introduced therein. Moreover, the hardening time of the binder is adjustable by regulation of its constituents.

While the binder is still fluid, the reinforcing member 2 is introduced therein to the bottom of hole h. The member 2 base surface roughness to enhance its integral setting with the binder. The member 2 may be made of metal, such as steel, plastic material or the like. The introduction of the reinforcing member into the binder causes the latter to extrude from the hole h and penetrate into any cracks or fissures in the soil or rock to cohese the same.

A cutter C is then introduced into hole H and then cuts a core S from the soil or rock as shown in FIG. 6. The cutter C prolongs the diameter of the hole H and the core consists of the reinforcing member 2, the hardened binder l and the intact sample of the soil or rock r surrounding the reinforcing member embedded in the binder.

The intact soil or rock mass of the core shows the undisturbed formation of the soil or rock mass in one continuous length.

FIG. 7 shows the apparatus for drilling the hole h, and this apparatus comprises a rotatably driven string of bore rods 3 coupled via a connection member 7 with a core barrel 4, such that the core barrel 4 can be driven by the rods 3. A drill bit 5 is secured to the barrel 4 at the lower end thereof and the bit cuts the hole h as the rods 3 are lowered in hole H. The core barrel 4 and the drill bit 5 have longitudinal, intercommunicating channels 10 for supply of cooling and wash water through rods 3 to the bit 5 during drilling and also for introducing binder 2 into hole h after the bit 5 has cut such hole. A guide means 6 serves to insure coaxial cutting of the hole h with respect to hole H. The guide means 6 is in the form of a sleeve member which fits within hole H and surrounds the core barrel 4. The connection member 7 initially holds the sleeve member in place until the sleeve member is engaged in the hole H. The sleeve member includes a number of radially inward flanges 11 (only one of which is shown) which engage barrel 4 to position the same and guide its descent in coaxial relation in hole H. The upper end of the sleeve member includes a further radially inward flange 12 which slidably and guidably engages rods 3 to facilitate descent of sleeve member 6 to the bottom of the hole H.

FIG. 8 shows apparatus for the insertion of the reinforcing member 2 into the binder l in the hole h, and this apparatus comprises positioning rods 8 to hold the reinforcing member 2 in a specific orientation so that member 2 will enter hole h substantially coaxially. A device 9 connects the lowermost rod 8 to the member 2, and the device 9 is of such construction as to release the member 2, when device 9 reaches the bottom of hole H, to enable removal of rods 8 and device 9 before the binder has hardened.

The construction of device 9 is well known to those skilled in the art and no details of the construction will therefore be set forth. Suffice to say that the invention is not directed to such details.

The positioning rods 8, device 9 and member 2 are provided with intercommunicating conduits 13 for flow of binder from hole It as the member 2 is introduced into the binder.

The guide means 6 of FIG. 7 may also be employed with the apparatus of FIG. 8 to guide the descent of rods 8 and member 2 in the holes.

Although the invention has been described with reference to a specific embodiment thereof, numerous variations and modifications can be made without departing from the scope and spirit of the invention ad defined in the attached claims.

What is claimed is:

l. A method of obtaining samples from soil and rock masses, said method comprising boring a hole into a mass to a depth, beyond which, a sample is to be removed, cutting a second hole in extension of the first hole and to a depth equal to the depth of the desired sample, the second hole being of smaller diameter than the first hole, filling the second hole with a binder and a reinforcing member, allowing the binder to harden and cutting a core from the mass inclusive of the binder and reinforcing member with an intact sample surrounding the same.

2. A method as claimed in claim 1 wherein said core has a diameter substantially equal to the first hole.

3. A method as claimed in claim 1 wherein the first and second holes are coaxial.

4. Apparatus for obtaining a sample from soil and rock masses in which a hole is bored to a depth, beyond which, a sample is to be removed, said apparatus comprising means for cutting a second hole in extension of the first hole and to a depth equal to the depth of the desired sample, means for introducing a binder into the second hole to fill the same, means for introducing a reinforcing member into the binder, and

means for cutting a core from the mass, said core being inclusive of the binder and reinforcing member with an intact sample surrounding the same.

5. Apparatus as claimed in claim 4 wherein said means for cutting the second hole comprises rotatable bore rods, a core barrel driven by said bore rods, a drill bit on said core barrel, and guide means for guiding the travel of said core barrel.

6. Apparatus as claimed in claim 5 wherein said guide means comprises a sleeve member engaged in said first hole and including means guidably engaging said core barrel.

7. Apparatus as claimed in claim 5 wherein said means for introducing the binder into the second hole is constituted by channels in the bore rods, core barrel, and drill bit.

8. Apparatus as claimed in claim 6 wherein said sleeve member includes means slidably engaging said bore rods.

9. Apparatus as claimed in claim 4 wherein said means for introducing a reinforcing member into the binder comprises positioning rods and means coupling the rods and the reinforcing member for the insertion of the reinforcing member into the second hole, the latter means being constructed to release the reinforcing member upon reaching the bottom of the first hole.

10. Apparatus as claimed in claim 9 wherein said reinforcing member and the means which couples the rods and reinforcing member are provided with channels for outflow of binder from the second hole when the reinforcing member is inserted thereinto. 

1. A method of obtaining samples from soil and rock masses, said method comprising boring a hole into a mass to a depth, beyond which, a sample is to be removed, cutting a second hole in extension of the first hole and to a depth equal to the depth of the desired sample, the second hole being of smaller diameter than the first hole, filling the second hole with a binder and a reinforcing member, allowing the binder to harden and cutting a core from the mass inclusive of the binder and reinforcing member with an intact sample surrounding the same.
 2. A method as claimed in claim 1 wherein said core has a diameter substantially equal to the first hole.
 3. A method as claimed in claim 1 wherein the first and second holes are coaxial.
 4. Apparatus for obtaining a sample from soil and rock masses in which a hole is bored to a depth, beyond which, a sample is to be removed, said apparatus comprising means for cutting a second hole in extension of the first hole and to a depth equal to the depth of the desired sample, means for introducing a binder into the second hole to fill the same, means for introducing a reinforcing member into the binder, and means for cutting a core from the mass, said core being inclusive of the binder and reinforcing member with an intact sample surrounding the same.
 5. Apparatus as claimed in claim 4 wherein said means for cutting the second hole comprises rotatable bore rods, a core barrel driven by said bore rods, a drill bit on said core barrel, and guide means for guiding the travel of said core barrel.
 6. Apparatus as claimed in claim 5 wherein said guide means comprises a sleeve member engaged in said first hole and including means guidably engaging said core barrel.
 7. Apparatus as claimed in claim 5 wherein said means for introducing the binder into the second hole is constituted by channels in the bore rods, core barrel, and drill bit.
 8. Apparatus as claimed in claim 6 wherein said sleeve member includes means slidably engaging said bore rods.
 9. Apparatus as claimed in claim 4 wherein said means for introducing a reinforcing member into the binder comprises positioning rods and means coupling the rods and the reinforcing member for the insertion of the reinforcing member into the second hole, the latter means being constructed to release the reinforcing member upon reaching the bottom of the first hole.
 10. Apparatus As claimed in claim 9 wherein said reinforcing member and the means which couples the rods and reinforcing member are provided with channels for outflow of binder from the second hole when the reinforcing member is inserted thereinto. 